vhost

overlay/tun_linux.go

@@ -5,7 +5,6 @@ package overlay
 
 import (
 	"fmt"
-	"io"
 	"net"
 	"net/netip"
 	"os"
@@ -17,15 +16,19 @@ import (
 	"github.com/gaissmai/bart"
 	"github.com/sirupsen/logrus"
 	"github.com/slackhq/nebula/config"
+	"github.com/slackhq/nebula/overlay/vhostnet"
+	"github.com/slackhq/nebula/packet"
 	"github.com/slackhq/nebula/routing"
 	"github.com/slackhq/nebula/util"
+	"github.com/slackhq/nebula/util/virtio"
 	"github.com/vishvananda/netlink"
 	"golang.org/x/sys/unix"
 )
 
 type tun struct {
-	io.ReadWriteCloser
+	file        *os.File
 	fd          int
+	vdev        []*vhostnet.Device
 	Device      string
 	vpnNetworks []netip.Prefix
 	MaxMTU      int
@@ -40,7 +43,8 @@ type tun struct {
 	useSystemRoutes           bool
 	useSystemRoutesBufferSize int
 
-	l *logrus.Logger
+	isV6 bool
+	l    *logrus.Logger
 }
 
 func (t *tun) Networks() []netip.Prefix {
@@ -102,7 +106,7 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, multiqueu
 	}
 
 	var req ifReq
-	req.Flags = uint16(unix.IFF_TUN | unix.IFF_NO_PI)
+	req.Flags = uint16(unix.IFF_TUN | unix.IFF_NO_PI | unix.IFF_TUN_EXCL | unix.IFF_VNET_HDR | unix.IFF_NAPI)
 	if multiqueue {
 		req.Flags |= unix.IFF_MULTI_QUEUE
 	}
@@ -112,20 +116,47 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, multiqueu
 	}
 	name := strings.Trim(string(req.Name[:]), "\x00")
 
+	if err = unix.SetNonblock(fd, true); err != nil {
+		_ = unix.Close(fd)
+		return nil, fmt.Errorf("make file descriptor non-blocking: %w", err)
+	}
+
 	file := os.NewFile(uintptr(fd), "/dev/net/tun")
+
+	err = unix.IoctlSetPointerInt(fd, unix.TUNSETVNETHDRSZ, virtio.NetHdrSize)
+	if err != nil {
+		return nil, fmt.Errorf("set vnethdr size: %w", err)
+	}
+
+	flags := 0
+	//flags = //unix.TUN_F_CSUM //| unix.TUN_F_TSO4 | unix.TUN_F_USO4 | unix.TUN_F_TSO6 | unix.TUN_F_USO6
+	err = unix.IoctlSetInt(fd, unix.TUNSETOFFLOAD, flags)
+	if err != nil {
+		return nil, fmt.Errorf("set offloads: %w", err)
+	}
+
 	t, err := newTunGeneric(c, l, file, vpnNetworks)
 	if err != nil {
 		return nil, err
 	}
-
+	t.fd = fd
 	t.Device = name
 
+	vdev, err := vhostnet.NewDevice(
+		vhostnet.WithBackendFD(fd),
+		vhostnet.WithQueueSize(8192), //todo config
+	)
+	if err != nil {
+		return nil, err
+	}
+	t.vdev = []*vhostnet.Device{vdev}
+
 	return t, nil
 }
 
 func newTunGeneric(c *config.C, l *logrus.Logger, file *os.File, vpnNetworks []netip.Prefix) (*tun, error) {
 	t := &tun{
-		ReadWriteCloser:           file,
+		file:                      file,
 		fd:                        int(file.Fd()),
 		vpnNetworks:               vpnNetworks,
 		TXQueueLen:                c.GetInt("tun.tx_queue", 500),
@@ -133,6 +164,9 @@ func newTunGeneric(c *config.C, l *logrus.Logger, file *os.File, vpnNetworks []n
 		useSystemRoutesBufferSize: c.GetInt("tun.use_system_route_table_buffer_size", 0),
 		l:                         l,
 	}
+	if len(vpnNetworks) != 0 {
+		t.isV6 = vpnNetworks[0].Addr().Is6() //todo what about multi-IP?
+	}
 
 	err := t.reload(c, true)
 	if err != nil {
@@ -220,7 +254,7 @@ func (t *tun) SupportsMultiqueue() bool {
 	return true
 }
 
-func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
+func (t *tun) NewMultiQueueReader() (TunDev, error) {
 	fd, err := unix.Open("/dev/net/tun", os.O_RDWR, 0)
 	if err != nil {
 		return nil, err
@@ -233,9 +267,17 @@ func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 		return nil, err
 	}
 
-	file := os.NewFile(uintptr(fd), "/dev/net/tun")
+	vdev, err := vhostnet.NewDevice(
+		vhostnet.WithBackendFD(fd),
+		vhostnet.WithQueueSize(8192), //todo config
+	)
+	if err != nil {
+		return nil, err
+	}
 
-	return file, nil
+	t.vdev = append(t.vdev, vdev)
+
+	return t, nil
 }
 
 func (t *tun) RoutesFor(ip netip.Addr) routing.Gateways {
@@ -243,29 +285,6 @@ func (t *tun) RoutesFor(ip netip.Addr) routing.Gateways {
 	return r
 }
 
-func (t *tun) Write(b []byte) (int, error) {
-	var nn int
-	maximum := len(b)
-
-	for {
-		n, err := unix.Write(t.fd, b[nn:maximum])
-		if n > 0 {
-			nn += n
-		}
-		if nn == len(b) {
-			return nn, err
-		}
-
-		if err != nil {
-			return nn, err
-		}
-
-		if n == 0 {
-			return nn, io.ErrUnexpectedEOF
-		}
-	}
-}
-
 func (t *tun) deviceBytes() (o [16]byte) {
 	for i, c := range t.Device {
 		o[i] = byte(c)
@@ -689,8 +708,14 @@ func (t *tun) Close() error {
 		close(t.routeChan)
 	}
 
-	if t.ReadWriteCloser != nil {
-		_ = t.ReadWriteCloser.Close()
+	for _, v := range t.vdev {
+		if v != nil {
+			_ = v.Close()
+		}
+	}
+
+	if t.file != nil {
+		_ = t.file.Close()
 	}
 
 	if t.ioctlFd > 0 {
@@ -699,3 +724,65 @@ func (t *tun) Close() error {
 
 	return nil
 }
+
+func (t *tun) ReadMany(p []*packet.VirtIOPacket, q int) (int, error) {
+	n, err := t.vdev[q].ReceivePackets(p) //we are TXing
+	if err != nil {
+		return 0, err
+	}
+	return n, nil
+}
+
+func (t *tun) Write(b []byte) (int, error) {
+	maximum := len(b) //we are RXing
+
+	//todo garbagey
+	out := packet.NewOut()
+	x, err := t.AllocSeg(out, 0)
+	if err != nil {
+		return 0, err
+	}
+	copy(out.SegmentPayloads[x], b)
+	err = t.vdev[0].TransmitPacket(out, true)
+
+	if err != nil {
+		t.l.WithError(err).Error("Transmitting packet")
+		return 0, err
+	}
+	return maximum, nil
+}
+
+func (t *tun) AllocSeg(pkt *packet.OutPacket, q int) (int, error) {
+	idx, buf, err := t.vdev[q].GetPacketForTx()
+	if err != nil {
+		return 0, err
+	}
+	x := pkt.UseSegment(idx, buf, t.isV6)
+	return x, nil
+}
+
+func (t *tun) WriteOne(x *packet.OutPacket, kick bool, q int) (int, error) {
+	if err := t.vdev[q].TransmitPacket(x, kick); err != nil {
+		t.l.WithError(err).Error("Transmitting packet")
+		return 0, err
+	}
+	return 1, nil
+}
+
+func (t *tun) WriteMany(x []*packet.OutPacket, q int) (int, error) {
+	maximum := len(x) //we are RXing
+	if maximum == 0 {
+		return 0, nil
+	}
+
+	err := t.vdev[q].TransmitPackets(x)
+	if err != nil {
+		t.l.WithError(err).Error("Transmitting packet")
+		return 0, err
+	}
+	return maximum, nil
+}
+
+func (t *tun) RecycleRxSeg(pkt *packet.VirtIOPacket, kick bool, q int) error {
+	return t.vdev[q].ReceiveQueue.OfferDescriptorChains(pkt.Chains, kick)
+}